The rapid development and widespread use of electronic devices have produced abundant electromagnetic waves, which affects the operation of other electronic equipment and even results in hazardous effects to human health. Therefore, lightweight, high-performance electromagnetic interference (EMI) shielding and microwave absorption (MA) materials are essential for controlling electromagnetic pollution and protecting the human body and other surrounding systems in civil or military applications. A new 2D MXene materials has attracted expanded attention latterly, which has special layered structure, large specific surface area, abundant natural defects and special metallic features. It has been extensively studied in electromagnetic interference shielding and microwave absorption. This paper introduces the synthesis methods and the characteristics of Ti3C2Tx MXene, and summarizes the latest research and applications of Ti3C2Tx MXene in the properties of electromagnetic shielding and microwave absorption in recent years. The prime novelty part of this review is to emphasize the effects of the synthesis process, structural design and the introduction of various materials to form different composites on the electromagnetic properties of Ti3C2Tx MXene. In the end, future prospects have been proposed to conquer the current barriers to prepare most progressive EMI shielding and MA materials for coming use objectively.

Recent advances in MXenes composites for electromagnetic interference shielding and microwave absorption

Antenna-in-package (AiP) technology, in which there is an antenna (or antennas) with a transceiver die (or dies) in a standard surface-mounted device, represents an important antenna and packaging technology achievement in recent years. AiP technology has been widely adopted by chipmakers for 60-GHz radios and gesture radars. It has also found applications in 77-GHz automotive radars, 94-GHz phased arrays, 122-GHz imaging sensors, and 300-GHz wireless links. It is believed that AiP technology will also provide elegant antenna and packaging solutions to the fifth generation and beyond operating in the lower millimeter-wave (mmWave) bands. Thus, one can conclude that AiP technology has emerged as the mainstream antenna and packaging technology for various mmWave applications. This article will provide an overview of the development of AiP technology. It will consider antennas, packages, and interconnects for AiP technology. It will show that the antenna choice is usually based on those popular antennas that can be easily designed for the application, that the package choice is governed for automatic assembly, and that the materials and processes choices involve tradeoffs among constraints, such as electrical performance, thermal–mechanical reliability, compactness, manufacturability, and cost. This article also shows a probe-based setup to measure mmWave AiP impedance and radiation characteristics. It goes on to give AiP examples implemented, respectively, in a low-temperature co-fired ceramic, an embedded wafer level ball grid array process, and a high-density interconnect processes. Finally, this article will summarize and present some recommendations on research topics to further the state of the art of AiP technology.

An Overview of the Development of Antenna-in-Package Technology for Highly Integrated Wireless Devices

Silicon-based millimeter-wave (mm-wave) phased-array technologies are enabling directional wireless data communications at Gb/s speeds. In this paper, we review and discuss the challenges of implementing a multichip phased-array antenna module for mm-wave applications using organic buildup substrate technology. A prototype test vehicle has been fabricated and studied to evaluate the antenna and interconnect performance, dielectric properties, package substrate warpage conditions at different temperatures, chip- and board-level joint process reliability, and thermal management feasibility for cooling. Based on the learning from the test vehicle, an organic-based multilayered phased-array antenna package for 28-GHz mm-wave radio access applications is implemented. The package incorporates 64 dual-polarized antenna elements and features an air cavity common to all antennas. Direct probing measurements on a single-antenna element of the package show over 3 GHz of bandwidth and 3-dBi gain at 28 GHz. A phased-array transceiver module has been developed with the package; the module includes four SiGe BiCMOS ICs attached using flip-chip assembly. Module-level measurements in the TX mode show a 35-dB near-ideal output power increase for 64-element power combining; 64-element radiation pattern measurements are reported with a steering range of ± 50° without tapering in off-boresight directions, and 64-element radiation pattern measurements with tapering show achievement of a sidelobe level lower than −20 dB. The transceiver modules achieved 20.64-Gb/s throughput with 256 QAM and 800-MHz bandwidth in direct over-the-air link measurement results.

Development, Implementation, and Characterization of a 64-Element Dual-Polarized Phased-Array Antenna Module for 28-GHz High-Speed Data Communications

In this study, advanced packaging is defined. The kinds of advanced packaging are ranked based on their interconnect density and electrical performance, and are grouped into 2-D, 2.1-D, 2.3-D, 2.5-D, and 3-D IC integration, which will be presented and discussed. Chiplet design and heterogeneous integration packaging provide alternatives to the system on chips (especially for advanced nodes) will be discussed. Different substrates, such as size, pin-count, and metal linewidth and spacing for advanced packaging, are examined. The lateral communication between chiplets, such as the silicon bridges embedded in organic build-up package substrate and fan-out epoxy molding compound, as well as flexible bridges, will be presented. Fan-in packaging, such as the six-side molded wafer-level chip-scale package (WLCSP) and its comparison with the ordinary WLCSP, are presented. Fan-out packaging, such as the chip-first with die face-up, chip-first with die face-down, and chip-last and their difference, will be provided. Low-loss dielectric materials for high-speed and high-frequency applications in advanced packaging will be presented. Flip-chip assembly by mass reflow, thermocompression bonding, and bumpless hybrid bonding will be briefly mentioned first.

Recent Advances and Trends in Advanced Packaging

Increasing data rates, spectrum efficiency, and energy efficiency have been driving major advances in the design and hardware integration of RF communication networks. In order to meet the data rate and efficiency metrics, fifth-generation (5G) networks have emerged as a follow-on to 4G and projected to have $100\times $ higher wireless date rates and $100\times $ lower latency than those with current 4G networks. Major challenges arise in the packaging of radio frequency front-end modules because of the stringent low signal-loss requirements in the millimeter-wave frequency bands, and precision-impedance designs with smaller footprints and thickness. Heterogeneous integration in 3-D ultrathin packages with higher component densities and performance than with the existing 2-D packages is needed to realize such 5G systems. This article reviews the key building blocks of 5G systems and the underlying advances in packaging technologies to realize them.

A Review of 5G Front-End Systems Package Integration

Increasing data rates, spectrum efficiency and energy efficiency have been driving major advances in the design and hardware integration of RF communication networks. In order to meet the data rate and efficiency metrics, 5G networks have emerged as a follow-on to 4G, and projected to have 100X higher wireless date rates and 100X lower latency than those with current 4G networks. Major challenges arise in the packaging of radio-frequency front-end modules because of the stringent low signal-loss requirements in the millimeter-wave frequency bands, and precision-impedance designs with smaller footprints and thickness. Heterogeneous integration in 3D ultra-thin packages with higher component densities and performance than with the existing 2D packages is needed to realize such 5G systems. This paper reviews the key building blocks of 5G systems and the underlying advances in packaging technologies to realize them.

Package-integrated and ultra-thin low-pass filter (LPF) and bandpass filter (BPF) with footprint smaller than $0.5\lambda _{0}\times 0.5\lambda _{0}\times 0.025\lambda _{0}$ at the operating frequencies of 28- and 39-GHz bands are presented for 5G and mm-wave small-cell application. Such package integration of 5G filters with ultrashort 3-D interconnects allows for low interconnect losses that are similar to that of on-chip filters, but low component insertion loss of off-chip discrete filters. These thin-film filters exhibit a cross-sectional height of $188.5~\mu \text{m}$ and can be utilized either as embedded components or integrated passive devices in module packages. Three topologies of LPF and BPF in total are modeled, designed, and fabricated on precision thin-film buildup layers on glass substrate as a core. Large-area panel-compatible semiadditive patterning (SAP) process is utilized to form high-precision topologies to aid the low-cost fabrication of ultraminiaturized filters. SAP also enables the realization of ultra-thin traces to precisely model high-impedance inductive lines compared to conventional subtractive etching and printing techniques. This results in filters with low insertion loss, low VSWR, and high selectivity. The simulated and measured results of filters show an excellent correlation.

First Demonstration of Compact, Ultra-Thin Low-Pass and Bandpass Filters for 5G Small-Cell Applications

A broadband and miniaturized planar Yagi antenna-in-package (AiP) design for the fifth-generation (5G) wireless communication is proposed The monopole taper radiator is adopted for the proposed Yagi antenna design to miniaturize the size, extend the bandwidth, and simplify the feeding network The proposed AiP design is broadband enough to cover all three 5G New Radio bands simultaneously The high-precision high-resolution multilayered glass packaging fabrication process with a new low-loss polymer material coating is adopted to realize the circuit The operation band is from 2425 to 40 GHz and the fractional bandwidth is 49% The overall size for an antenna element is 305 mm × 556 mm, which is equal to 025 $\lambda _0$ × 045 $\lambda _0$  The measured $S_{11}$ is smaller than $-$ 10 dB within the entire band and the gain is larger than 4 dBi A two-by-one array using the proposed element is also demonstrated with a gain higher than 62 dBi within the entire band Compared with previous works, the proposed AiP design can cover all 5G bands with a competitive size Thus, it is suitable to be applied to massive arrays and easily integrated into packages to achieve compact system-in-package applications while resolving numerous current 5G challenges, including millimeter-wave (mm-wave) path loss and transmission loss

Broadband and Miniaturized Antenna-in-Package (AiP) Design for 5G Applications

High-performance and ultra-miniaturized mm-wave building block structures were demonstrated on panel-scale processed 3D glass packages for high-speed 5G communication standards at 28 and 39 GHz bands. To demonstrate the benefits of glass for 5G communications, various topologies of microstrip-fed patch antennas for different resonant frequencies and compact conductor-backed co-planar waveguides were modeled and designed for high bandwidth and efficiency in the mm-wave bands. The simulation results for insertion loss, antenna gain, and bandwidth are consistent with the measured values on the glass substrates. The fabricated conductor-backed coplanar waveguides show insertion losses of 0.2 –0.3 dB/mm with a channel length of 1.86 mm, and the fabricated antennas have more than around 6% bandwidth in the frequency range of 35 to 39 GHz.

https://www.computer.org/csdl/pds/api/csdl/proceedings/download-article/12OmNzIUfRT/pdf

Atom Watanabe

Papers

A Review of 5G Front-End Systems Package Integration

A Review of 5G Front-End Systems Package Integration

First Demonstration of Compact, Ultra-Thin Low-Pass and Bandpass Filters for 5G Small-Cell Applications

Broadband and Miniaturized Antenna-in-Package (AiP) Design for 5G Applications

First Demonstration of 28 GHz and 39 GHz Transmission Lines and Antennas on Glass Substrates for 5G Modules